1. Field of the Invention
The present invention relates to a cranking device of an internal combustion engine.
2. Description of Related Art
A cranking device for internal combustion engines of the type mentioned in the introduction is known from the published German utility model document DE 297 04 299 U1. The cranking device for internal combustion engines described therein has a cranking motor, which is disposed in a pole casing and has a drive shaft that is in operative connection to a driven shaft via a reduction gear. The driven shaft is part of a starter-pinion drive having an overrunning clutch and a starting pinion. The starting pinion is disposed on the driven shaft in a manner that allows axial displacement and engagement with the ring gear of a starter gear of the internal combustion engine by axial displacement.
The drive shaft of the cranking motor carries an armature and a commutator having carbon brushes together with a current supply. Via its end on the commutator side, the drive shaft is supported in a commutator bearing; on its opposite side, it is accommodated in an axial bore of the driven shaft with the aid of a lug. The drive shaft drives the driven shaft via a planetary gear. For this purpose, the driven shaft has an external gearing which drives planetary gears, which in turn are in comb-type engagement with a fixed internal gear. The planetary gears are supported on pins pressed into a flange of the driven shaft at the extremity. The extreme flange is facing the cranking motor. The driven shaft is supported behind the flange in a bore of the bearing of an intermediate bearing, and its other end is supported in a bearing of a housing which seals the pole casing and is clamped to it with the aid of tension rods. However, in such a system particles from the region of the commutator travel to the region of the armature and downstream components.